Method of casting wheels and other articles



y 7, 1932- w. M. DUNCAN 1,859,079

METHOD OF CASTING WHEELS AND OTHER ARTICLES Filed June '22, 1931 IN VEN TOR ATTORNE K Patented May 17, 1932 WILLIAM M. DUNCAN, or Amen, ILLINOIS METHOD or CASTING WHEELS AND ornnnhnrronns Application filed June 22, 1931. Serial-Ito. 545,970.

This invention relates to certain new and useful improvements in method of casting wheels and other articles, the peculiarities ofwhich will be hereinafter fully described and claimed.

This application is a continuation in part of my prior application on improvements in cast wheels, Serial No. 506,699, filed January 5, 1931.

The main objects of my invention are first, to form a homogeneous outer surface of a circular, cylindrical or other shape of casting; second, to protect a chilled surface on such a casting from the heat of spokes or other integral connections between adjacent portions of said article so as to obtain a chilled surface that is homogeneous and without soft spots; third, to provide inner and outer walls for one of said portions so that the heat of said integral connections from the inner wall to the other portion of the casting is kept from afiecting the chilled surface of the outer wall; fourth, to shield the chilled surface of one wall from the heat of the other wall; fifth, to provide for the escape of gases through the inner wall and maintain the outer wall in solid homogeneous condition; sixth, to lessen the shrinkage strains on said integral connections; seventh, to retard the withdrawal of heat from an inner wall and its integral connections to an adjacent portion opposite an outer wall, and

thereby retain the necessary heat for proper annealing of the casting in the soaking pit; and eighth, to develop the full strength of the spokes or other integral connections.

In the accompanying drawings in which like'reference numerals indicate correspond-' ing. parts, 7

Fig. 1 represents a-plan view of a wheel embodying my invention, the upper half being a face view and the lower half being a sectional plan through the tread to show the construction, and indicating the application of a chill and a sand mold; and

posed chamber needs support.

2, a cross section ofFig. 1 on the line Ordinarily, that section of the rim of a wheel, gear or other article having spokes that is radially. out from a spoke integral therewith, willnot chill'at all,or at least not to thedepth ofchill'at other parts of-the rim', due tothe additional body of metal in the spoke; Also the shrinkage of thesolid spoke connecting the rim and hub tends to 5 cause a depression in the rim if thin,-or subject it to internalshrinkage strains ifit be thick,fwhen the cast iron orother metal cools. In my construction however, the rim of the wheel andgear, and the cylinder of the roller, is of double wall construction. The outer wall is preferably subjected to the action of a chill, and the inner wall is integral with solid spokes connecting it to the hub. The outeriwall is continuous and the inner wall is parallel'to it but provided with openings where the dry sand 'core forming the inter- These openings also vent the gases formed between these walls. a i V y wReferring tothe drawings, the numerall designates a hub having radiating spokes 2, preferably solid and integrally connecting said hub with the hollow rim constituting a one-piece casting of cast iron or other suitable metal. 7

Thisrim comprises an outer wall?) and an inner wall 4 spaced therefrom and preferably parallelto the outer wall and connected by front and rear face walls forming an interposed chamber preferably extending completely around therim.g Said outer wall 3 is practically uniform in section and separated by the interposed chamber from the solid spokes 2 that are integral at their outer ends with said-inner wall 4. 1

FA: series of spaced rectangular or other shaped openings 5 are formed in said inner wall preferably about a third of the depth of said inner wall. These openings divide the ner wall into partial segments 6 as shown in the figures. They also serve to support radial inward projections from a dry sand core 8 having an outer circular portion 9 adapted to space apart the said walls and form the inuniform chilling effect upon the substantially uniform thickness of the outer wallof my hollow rim, so thata uniformhomogeneouschilling effect is produced on the outer surface of the outer wall. Since the-solid'spokes I claim:

The method of casting a circular article having a double walled hollow rim integrally connected by spokes to a hub, in a sand mold, consisting of chilling the outer wall of said rim, shielding the inner wall opposite the ends of the spokes from the said chilling action so as to retard the loss of heat therefrom and to prevent strains and fractures whlle the article 1s cooling.

In testimony whereof I have afiixed my signature.

WILLIAM M. DUNCAN.

are connected to the inner wall and the in-' terp'osed chamber separates the inneriwall from the outer wall as shown, the heat from 1 said spokes has practically no effect uponthe outer wall'aswould be'the: case if thespo'kes were directly connected thereto. Furthermore, the dry sand core forming saidchamb'er serves to retard'the withdrawal ofheat'by the chill from the inner wall, and'thus shields the inner wall;- More "heat is thus retained in the spokes and'hub, which heat 'is' vital for proper annealing inthe soaking pit. Strains are more perfectly removedand lesslia bi'lity of fracture of "the spokes. is obtained;-

Between' the outer' and inner'wallsi'I provide bridge connections of cylindrical or other form 13 integrally connectingnnd'hracing the two walls-TThese bridge; connections areshown opposite the partial segments' alternating with the segment's at the' ends: of the'spokes, so that the segments atrthe'ends of the spokes are not directllynonnected to the outer wall except bythe front :andzback walls of the rim; The'sebridgeconnections may be otherwise spaced ifdesired;

Thus it will be seen that the endsiofthe solid spoke's and'the partialsegments of the inner wall to which they are integrally con nected are practically heat insulated from the outer' chilled wall and have practically no extra heating elfe'ct' upon the outer wall and consequent formation of soft spots, which is the casein the usual construction. Therefore the-chillmay be ofuniformfcross section, instead of having the irregular enlargement of cross'section used in; the endeavor to compensate for the extra heat at different portions of the-tread-opposite the spokes; furthermore,by'mymethod more heat v is retained in the spokes and thehub and the metal of the spokes is lesssubjectto internal strains and consequent fracture.

These spokes can thus'be madej'of sufiicient size to'provide 05 the strength required-"in rough usage. V 

